1. Field of the Invention
The present invention relates to land grid array (LGA) connector assemblies, and particularly to an LGA connector assembly adapted for receiving an LGA central processing unit (CPU) therein and electrically connecting the CPU with a printed circuit board (PCB).
2. Description of the Prior Art
Referring to FIG. 3, a conventional LGA connector assembly 9 is adapted for electrically connecting an LGA CPU (not shown) having a multiplicity of metallic contact pads with a PCB (not shown). The LGA connector assembly 9 comprises an insulative base 91 receiving a plurality of electrical contacts (not shown), and a lever 92 and a metal clip 93 pivotally mounted to two opposite ends of the base 91 respectively.
The lever 92 comprises a pair of locating portions 922, an offset securing portion 921 between the locating portions 922, and a handle portion 923 extending perpendicularly from an end of one of the locating portions 922. The clip 93 comprises a lip 931 at an end thereof, and a pair of spaced mounting portions 932 extending arcuately from an opposite end thereof.
The base 91 defines a rectangular cavity 911 in a middle thereof, a pair of spaced slots 912 at one end thereof, and a trapezoidal recess 913 at an opposite end thereof. The base has a forewall 914. The cavity 911 is adapted for receiving the CPU therein. A multiplicity of passageways (not shown) is defined in a portion of the base 91 under the cavity 911, the passageways receiving a corresponding number of the contacts therein, respectively. Also referring to FIG. 4, the mounting portions 932 of the clip 93 are received in the corresponding slots 912, to pivotably mount the clip 93 to the base 91. The base 91 comprises two spaced upper ears 917 extending from an upper section of the forewall 914, two spaced lower ears 918 extending from a lower section of the forewall 914, and a pair of blocks 915 each mounted to a respective one of the lower ears 918. The upper and lower ears 917, 918 cooperatively define a channel 916 therebetween, the channel 916 being in communication with the recess 913. The locating portions 922 of the lever 92 are received in the channel 916, and the securing portion 921 of the lever 92 is received in the recess 913. The blocks 915 are mounted to the corresponding lower ears 917 to retain the locating portions 922 within the channel 916.
In use, the base 91 is mounted to and electrically connected with the PCB. The clip 93 and the handle portion 923 of the lever 92 are oriented perpendicular to the base 91, with the securing portion 921 disposed above the locating portions 922. The CPU is mounted in the cavity 911, with the metallic contact pads of the CPU loosely attached on the corresponding contacts of the base 9. The clip 93 is rotated down to loosely contact the CPU. The handle portion 923 is rotated downwardly, thus rotating the securing portion 921 downwardly. The securing portion 921 contacts the lip 931 of the clip 93 and presses the lip 931 downwardly. When the handle portion 923 has reached a horizontal position, the securing portion 921 is tightly engaged with the lip 931, and the metallic contact pads of the CPU are firmly attached on the contacts of the base 91. The LGA connector assembly 9 thus electrically connects the CPU with the PCB.
With the prevailing trend toward miniaturization of computers, the sizes of LGA connector assemblies used in computers are steadily becoming smaller. In contrast, the number of contacts used in LGA connectors is increasing to meet the need for more signal transmission. These considerations bear on the conventional LGA connector assembly 9 as follows. During the rotation of the lever 92 to force the metallic contact pads of the CPU on the contacts of the base 91, the metal clip 93 and the lever 92 exert forces on the base 91. The forces acting on portions of the base 91 near the slots 912 and at the channel 916 are greater than those acting on other portions of the base 91. Therefore the base 91 is liable to deform and warp. When deformation or warpage occurs, some contacts cannot firmly contact the metallic contact pads of the CPU, which disrupts the electrical connection between the CPU and the PCB.
In addition, the upper and lower ears 917, 918 are thinner than other portions of the base 91, and are typically made of non-rigid insulative material such as plastic. When the lever 92 is rotated downwardly to press the lip 931 downwardly, the upper ears 917 and/or the lower ears 918 are liable to deform and warp due to compression from the locating portions 922 of the lever 92. When deformation or warpage occurs, the lever 92 is liable to break out from the channel 916.
A new LGA connector assembly that overcomes the above-mentioned disadvantages is desired.
Accordingly, an object of the present invention is to provide a land grid array (LGA) connector assembly for electrically connecting an electronic package such as an LGA central processing unit (CPU) with a circuit substrate such as a printed circuit board (PCB), wherein the LGA connector assembly has a base that resists deformation and warpage.
Another object of the present invention is to provide an LGA connector assembly which has a lever mechanism configured to minimize the risk of the lever breaking out from the LGA connector assembly in use.
To achieve the above-mentioned objects, an LGA connector assembly in accordance with a preferred embodiment of the present invention comprises an insulative base, a stiffener mounted to the base, a lever pivotally mounted to one end of the base, and a metal clip pivotally mounted to an opposite end of the base for engaging with the lever. The base defines a rectangular cavity in a middle thereof and a plurality of rectangular holes in two opposite lateral sides thereof. The base has a forewall at an end thereof. The stiffener comprises a pair of metal reinforcing members covering the opposite lateral sides of the base. Each reinforcing member comprises a top portion, a flange depending perpendicularly from an outside edge of the top portion, and three projecting portion depending perpendicularly from an opposite inner edge of the top portion for engaging with the holes of the base. When the reinforcing members are mounted to the base, the ends of the flanges and the forewall of the base cooperatively define a channel. Each of the flanges defines a pivot bore at an end of the channel. The lever is received in the channel with pivoting in the pivot bores of the reinforcing members. Thus, when the lever and the clip are rotated to tightly attach a CPU in the LGA connector assembly, the base is able to withstand forces from the clip without any deformation and warpage, and the lever is reliably retained in the channel with minimal risk of breaking out from the channel.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which: